A reader's comment to the blog post Keeping the Money Where It Belongs:
I think you are very much on the spot here. Building up trust is key for using existing channels to report bribery. This needs to come with making anti-corruption institutions sufficiently independent and provide them with the necessary power to prosecute cases.
Civil Society offers such as Transparency International's Advocacy and Legal Advice Centres (http://blog.transparency.org/2009/06/03/paid-a-bribe/) can fill the void only in a very limited manner.
Not to forget and maybe equally important, and not necessarily included by the Barometer data, is whistleblower protection and legislation. An issue Transparency International has just started to work on in Europe.